Carbon X1 only displaying via monitor

[jdt2019]

Hi Guys,

I have a job from one of my customers. He owns a Carbon X1. His original fault was that he had dropped it whilst it had the charging cable inserted, it ended up making a mess of the USB C port on the charging cable and he was forced to replace it.

The thing is, he brought this to me with a perfectly running screen and 70% battery remaining. He had no charging cable when he dropped it in to me.
Heres a picture of the board:
https://imgur.com/a/Q5o1DfL


I started by powering it down and removing the back plate and looking around the power adapter for any signs of damage. I decicded to take off the metal cover that protects the USB C port and the USB C charging port. Heres what it looked like:
https://imgur.com/a/mCkEvdk

Then without the cover:
https://imgur.com/a/wZI6jzf

Everything appeared fine to me. I put the metal cover back on and put the rear casing back on.

I tried to boot it up. Thats when my stress levels went through the roof. Once I pressed the power, the keyboard backlights would come on, the fan would does its usual thing, except the screen was just blank. I could press the caps lock and function locks and the lights for those would work. I decided to plug a HDMI in and run it to my monitor. Bam, it would work plugged into an external display.

I have bought a new power adaptor, it went into the port as normal and began charging the battery. There is no damage to the port.

I am in a bit of a position but. The customer only asked me to assess the damage to the port and replace the charger. His screen was working when he dropped it into me. I can confirm that I was super delicate removing the plate cover from the photos above, I am paranoid about using the wrong screw's and am really diligent when it comes to opening up someones laptop. Has anyone got any ideas for me please?

I was reading other posts and was thinking the motherboard may be, well, dead, but it seems strange that the screen has turned off completely, just by me removing the cover. I have tried the function keys that could switch between external display to default display. Any help is really appreciated, I feel like I owe this guy a brand new laptop for no reason.

Please please help.

EDIT: I noticed the screen is on but very dim. Its like that from the very first boot page and no FN keys will increase the brightness.

[dr_st]

Welcome to the forum, and sorry to hear about your trouble.

Your description suggests that the screen is working but the backlight is not. Double-check that all the cables connecting LCD and motherboard are intact, connected securely and not damaged. You may try to disconnect, gently clean the contacts with some alcohol and reconnect.

If that does not help, then perhaps the fuse on the motherboard that governs the LCD backlight somehow blew out. There are folks that know the locations of the relevant fuses, how to test, and if need be, replace them; unfortunately, I am not one of them, but hopefully there is such a person on the forums.

[whizkid]

My X1C3 is also not backlit. It went out a few months ago. I finally took it to Micro Center, and while I was doing paperwork for the fix, the tech turned it on, and it worked! For weeks!

But alas, the backlight is now out again. The intermittent nature makes me think it's a connector, but I used the HMM to remove all the cables, clean them, and tighten again. I fear it's a loose connector (the machine has been dropped twice, and the display replaced twice already) and that even a replacement display ($450 parts and labor) would only work a short while. Oh, I'll have to ask for the warranty on the repair.

Otherwise, I'm going to attempt to repair the backlight. Wish me luck, or even better send me tips and links on how to do this!